One, You watch an extremely intelligent show, please TRY to look a bit more intelligent "Shud" is Should, thank you very much... Then again I cant expect anything better from a Twilight fan where the first page has 6 grammar and spelling errors. Anywho.
As a David Tennant fan, I dont believe he SHOULD have REGENERATED. David was the perfect doctor. (And adorable to boot!)
But as a Doctor Who fan, he should have. The doctor took too much radiation (for lack of a better word) to survive even as a "time-lord". As well as the doctor was always ment to change, so a change was needed eventually. I'm just glad it happened now, compared to during "Journey's End".
Also I don't think David Tennant would want to only be known as that guy that played the "Doctor".
No,Tennant was the best doctor to ever set foot in the TARDIS, and plus he was on his twelvth form,so it should be impossible. I don't think he was the perfect doctor, but very near the mark, and Matt smith's doctor, or at least what i've seen of him, is definitely not